1. Field of the Invention
The present invention relates to a handheld welding torch for electric-arc welding with a melting welding wire, having a wire feed unit for conveying the welding wire along a conveying axis arranged within a torch housing with a handle region, said wire feed unit including a drive unit with a rotation axis arranged vertically with respect to the conveying axis of the welding wire, a drive roller with a rotation axis and a counter roller with a rotation axis, and having a torch push-button.
2. Description of the Related Art
Basically, handheld welding torches having an integrated wire feed unit, called push-pull torches, are known from the prior art. A particular disadvantage of the known design variants is an unfavorable increase in weight, since constructional reasons lead to relatively large and heavy drive units being used. This increased weight of handheld welding torches having integrated wire feed units is a major disadvantage for the welder because it means that he has to handle a greater weight. Another aspect associated therewith is that the drive units currently in use are placed such that they exhibit an especially unfavorable distribution of weight. This is because the large and/or bulky drive units cannot be placed in a space-saving and ergonomically sensible manner. As a consequence, especially unfavorable ergonomic properties for handles are implemented and/or need to be implemented at the same time. The drive units currently in use cannot be integrated into standard welding torches since they consume too much space within the welding torch.
As a result, the only handheld welding torches currently available on the market exhibit these exact disadvantages. DE 40 09 391 A1, for example, describes a welding torch having a drive unit the axis of which is placed horizontally and transverse to the conveying axis of the welding wire. The transverse installation with respect to the conveying axis, however, requires much space so recesses and/or projections for the drive unit are needed in the housing of the welding torch. This makes handling and access even more difficult. By the same token, the unfavorable distribution of weight and the ergonomic properties of the handle are disadvantageous. Another disadvantage is that the bevel gears required here have poor performance, which has a considerable impact on thermal losses. This means that the poorer the performance is the higher thermal losses will be.
A further variant is described in AT 413 662 B. Here, the drive unit may be integrated into a robot welding torch or a handheld welding torch, with the handle of the welding torch being directed vertically downwards, similar to a pistol grip. The drive unit is integrated directly within the torch handle, which must necessarily be held by the user's hand. Substantially, the size of the torch handle is determined by the constructional size of the drive unit. A particular disadvantage that has been observed here is that the drive unit develops and subsequently releases heat, said heat being transferred directly to the torch handle and the hand of the welder, who necessarily holds the handle. In this type of design, this cannot be avoided since the drive unit and the torch handle form a single unit. Furthermore, the rotation axis of the drive is arranged aligning with the rotation axis of the drive roller, i.e. next to the conveying axis of the welding wire.